Mark Rober is a former NASA engineer who now spends his time as an internet personality. His core goals when developing a project are simplicity and creativity. I first read about Mark last year when he developed a giant Nerf gun and last month he was back in the news with the world’s largest Super Soaker.
The gun is now the Guinness World Record Holder for Largest Super Soaker, coming in at seven feet long and capable of shooting at speeds of 243 miles per hour and 2400 psi. Most of the video focuses on doing ‘cool’ stuff with a highly pressurized water gun, lots of food is cut into pieces with an incredibly accurate stream. I was most interested in the pressurized stream that battered an aluminum soda can before yielding the syrupy contents.
Beyond the spectacle of the video is a good, light explanation of much of the build and operation of the gun. Lonnie Johnson, former NASA engineer and creator of the original Super Soaker gun, is interviewed and talks about some design elements. Rober explains that most of the mass is in the handle because a low center of gravity helps for stability and movement. Two tanks, one of water and the other Nitrogen gas, sit in the handle to pressurize and deliver the water. One very interesting part of the design is the trigger – a ball valve needs to open and shut to allow the water to escape. Rober wanted a trigger motion instead of needing to turn a valve to fire the water, so he built a pneumatic piston to open and close the valve and tied that to a large trigger piece.
The video has an explanation segment where the full front face is removed to show the mechanism, but for regular use a small magnetic panel can be removed to fill the tanks back up with water. There’s a full parts list and parametric design files up on Dropbox. I imported the x_t files into SolidWorks and it’s great to see how closely the design matches up to the final product shown in the video. It’s also a great example for students to see that in a professional project, even if it’s a giant water gun instead of a vehicle’s fuel pump assembly, all of the components are named and numbered and correct assembly hierarchy is followed.
There’s a lot of sensationalism in this video and an unfortunate commercial for a DNA / genealogy website, but the fundamentals of engineering and design displayed have merit. Bob from I Like to Make Stuff has another shorter video that shows a little more of the straight construction of the project and the design trade offs that need to be made.